Slide-valve gear



May 27, 1924. I 1,495,333

J. KRUGER SLIDE VALVE GEAR Filed June 1. 1921 2 Sheets-Sheet 1.

) J. KRUGER SLIDE VALVE GEAR File Jun 1921. 2 Shawls-Sheet 2 -l 'atentecl May 27, 1924.

'UIUNIITED s 'rarrzsv 1,495,333 PATENT OFFICE. I

JoHANnEs KRTTGER, or OSTERHOLZ-SGHARMBECK, GERMANY.

SLIDE- VALVE GEAR.

Application filedJune 1. 1921. Serial No. 474,258.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.)

To all whom it may concern:

Be it known that I, JOI-IANNES Km'ienn, a citizen of the German Empire, residing at Osterholz -Scharmbeck, Germany, have invented certain new and useful Improvements in Slide-Valve Gears, for which I have filed application in Germany, May- 27, 1920, Patent No. 331,304, and of which the following is a specification.

My invention refers to slide-valve gear for steam engines and its particular object is to automatically arrest such valve gear in its end positions.

Slide valve gears for steam engines, and more especially for-steam pumps in which the distributing valve is controlled by the steam which at the end of the stroke flows from the working cylinder into a chamber at the front.v ofiv the distributing valve through a passage which in the endposition of the' piston is opened by *the latter, have already been made use of. There are further known steam, engine valve gears with two working; pistons mounted on the same piston rod and a chamber intermediate these pistons connected to the exhaust, this chamber communicating alternately with either of the front chambers of the piston valve. Engines controlled-in this manner offer the advantage of simple and cheap construction. The disadvantage of the hitherto known designs of this kind, however, is that the distribution valve is heldin an, inadequate manner in its end positions on the one; or other frontalside. Inthe center position of the workingpiston of asteam engine of this type, exhaust steam acts on both sidesof-the distribution valve, so that this distribution valve is notheld fixedly in position. j-Thus it may happen that on board ship the piston valve may be set in motion by the rolling of the vessel whereby the valvegear may be reversed at the improper moment.

. In order to overcome this'difficult-y, i. e.

not only to effect the'required movement of the controlling piston, but also; to keep the latter in vvthe required end position, I provide that the controlling piston at its two frontal sides, besides being under the influence of the frontal chambers hitherto used, is also acted upon by auxiliary steam chambers which have afsmaller sectional area than the remaining effective frontal surface of the controlling piston and which are connected to themain admission ducts of the steam cylinder in such a manner that each time the one particular steam chamber which happens to be opposite to the required end position of the controlling piston is supplied with live steam. Therefore, according to the present invention, the control valve is secured in the respective end position by the reliable medium of live steam.

In the drawings affixed to this specification and forming part thereof three modifications of a device embodyingmy invention are illustrated diagrammatically by way of example. In the drawings Fig. 1 is a longitudinal section of the first modification,

Figs. 2 and 3 being similar views showing the parts in different positions of the second modification which differs from the first modification in a detail regarding the steam conduits, while Fig. 4 is a longitudinal section of the third modification differing from Fig. 1 with regard to the slide valve.

Referring first to Figs. 1 'to 3 the modification shown in Figs..2 and 3 is identical with the one illustrated inFig. 1, excepting only the manner of connecting certain steam conduits which shall be described more particularly hereinafter. In all other with a lining P of a well known kind. Live steam enters through a central inlet 17, while the exhaust steam escapes'through lateral conduits 10 and 11. The lateral or end portions C and D of the valve box M are chambers, their cross section being smaller than the remaining end surfaces of the slide valve in the chambers C and D. The chambers A and B are closed by stationary pistons Q, and Q respectively, fixed to the valve box covers. In the modification shown in Fig. 1 chamber A is connected by a conduit 4 directly with the main steam passage 2, chamber B by a conduit 5 directly with the main steam passage 1, while in the modification shown in Figs. 2 and 3 chamber A communicates by way of a conduit 4 with an aperture of the valve box M disposed near the level of the upper end of the main steam passage 2, and chamber B is connected by a conduit 5 with an aperture disposed near the level of the main steam passage 1 the chambers A and B being thus connected in both forms crosswise with the main steam canals 2 and 1, respectively, the lefthand auxiliary chamber A with the righthand passage 2 and the righthand auxiliary chamber B with the lefthand passage 1.

The operation of this device is for both forms the following Assuming the slide valve E shown in Fig. 1 not to assume the middle position illustrated, but the right hand end position shown in Fig. 1 the double piston K K is on its way from the right to the left. In this right hand end position of the slide valve E live steam enters through the central inlet 17 and steam passage 2 into the righthand end portion of the working cylinder and causes the working piston to move to the left, while exhaust steam escapes from the working cylinder through passage 1 and the lefthand exhaust opening 10 of the valve box M. The righthand end portion D as well as the lefthand end portion C of the valve box communicate by the conduits 3 and 6, respectively, with the space between the two pistons K, and K which is connected by canal 12 with the righthand exhaust steam opening 11, whereby D and C are under exhaust steam pressure also. The

righthand auxiliary chamber B of the slide E communicates by conduit 5 with the ex haust steam canal 1 and is therefore under exhaust steam pressure as well. On the other hand the lefthand auxiliary chamber A of the slide communicates through conduit a with the live steam passage 2, whereby the slide is held immovably in the righthand end position shown in Fig. 2 by the live steam in chamber A.

When the working pistons K K reach the position illustrated in Figure 2, the righthand end space D of the valve casing M is connected through conduit 3 with the live steam in the righthand end space of the working cylinder N, whereas the steam-connections in the other chambers A, B and 0 remain at first the same, as described with reference to Figure 1. Thus, the. righthand auxiliary chamber B and the lefthand end space C is under exhaust steam pressure, while in the leftha-nd auxiliary chamber A and the righthand end space D there prevails live steam pressure. Inasmuch, however, as the effective end surface of the slide valve in the end space D is larger than the surface of the auxiliary chamber A, which counteracts it,'the slide valve E will be shifted into the lefthand end position shown in Figure 3 and the piston of the engine will thereby be reversed, so that now live steam enters through passage 1 into the lefthand end space of the working cylinder N and actson the piston K while the righthand end space of the working cylinder is connected through passage 2 with the exhaust steam sleeve "11. In consequence thereof also the righthand end space D, which is connected through port and conduit 3 with the righthand endspace of the working cylinder, and the lefthand auxiliary chamber A, which communicates through conduit a with the exhaust steam passage 2, are under exhaust steampressure. The same is true of the lefthand end space C, which remains in connection through conduit 6 with the space. between the two pistons K, and K, which. is permanently under exhaust steam pressure. 7 On the other hand, the righthand auxiliary chamber B now communicates through conduit 5 with the live steam passage 1. There fore, in the position of parts-shown in Figure 3, exhaust steam pressure exists in the two end chambers C- and D, as well as in the auxiliary chamber A, whereas live steam pressure exists in the righthand auxiliary chamber B, so that now the slide valve is, retained in its letthancl end position by the live steam in the righthand auxiliary chamber B.

These conditions remain unchanged until the iston 1& in moving from the left to the right, uncovers the port and conduit 6, whereby the left-hand and space C is connected with the lefthandi endspalceof the working cylinder, which isunder live steam pressure, so that live steam enters the space 0. On the other han hxthe steam conditions in the chambers A, Band D' remain at first unchanged, that is to say, the auxiliary chamber A and the end space- D are under exhaust steam pressure, the end space (1 and; the auxiliary chamber; B- under live steam pressure. However, as the effective end surface of the slide valve in chamber C is larger than the surface in the auxiliary chamber B- which counteracts it, the slide valve'is now shiftedfromthe lefthand end position of Figure 3 into the righthand endposition, the engine beingtherebyreversed, so that now therighth-and end space ot the working cylinder is connected through passage 2 with the live steam inlet 17, the lefthand end space through passage 1 with the exhaust through 10, while the steam conditions in the chambers A, B, C and D are now changed as described with reference to Figure 1, that is to say, exhaust steam pressure now exists in the end space D, which is connected through conduit 3 with the space between the two pistons K and K,, as well as in the auxiliary chamber B communicating through conduit 5 with the exhaust steam passage 1, and in the end space C which is now connected through conduit 6 with the exhaust steam side of the working cylinder, while the auxiliary chamber A communicating through conduit 4 with the live steam passage 2 is under live steam pressure, so that the slide valve is immovably retained in its righthand end position.

The modification disclosed in Figure 4 is substantially identical with the first modification illustrated in Figure 1 with the exception that in the modification of Figure 4 the two auxiliary chambers A and B are not arranged in the slide valve, but in the two covers of the valve casing,.while the pistons Q and Q form part of the slide valve. The cross sectional area of the auxiliary chambers A and B and the effective surface of the auxiliary pistons Q and Q, is here as well smaller than the remaining effective surface of the slide valve in the end spaces of the valve casing. The lefthand auxiliary chamber is again connected through conduit 4 with the righthand steam passage 2, the righthand auxiliary chamber B through the conduit 5 with the lefthand steam passage 1, both conduits 4 and. 5 extending down to the passages 2 and 1. The mode of operation and the effect of this modification is the same in all respects as described with reference to the modifications illustrated in Figures 13 and-it is, therefore, unnecessary to once more describe it.

I claim:

1. In a steam engine in combination, a cylinder, a double piston adapted to reciprocate within said cylinder, a distributing slide valve, and an exhaust port adapted to be connected with said cylinder by said valve, a chamber at each end of said valve adapted to be connected with the exhaust through the space enclosed by said double piston and near, the end of the piston stroke with the live steam space of said cylinder for throwing the valve, an auxiliary chamber of smaller sectional area than the effective surface of said slide valve at each end of said valve, a piston fitting in and forming a closure for each auxiliary chamber and a special connection, adapted to be controlled by said slide valve, between each auxiliary chamber and the live steam space on the opposite side of said cylinder for retaining the valve in thrown position.

2. In a steam engine in combination, a

cylinder, a double piston adapted to reciprocate within said cylinder, a distributing slide valve a casing for said valve and an exhaust port adapted to be connected with said cylinder by said valve, each end of said valve casing being adapted to be connected with the exhaust through the space enclosed by saiddouble piston and, near the end of the piston stroke with the live steam space of said cylinder for throwing the valve, an auxiliary chamber of smaller sectional area than the effective surface of said slide valve at each end of said valve casing, a piston integral with said valve fittin in and forming a closure for each auxillary chamber, and a special connection, adapted to be controlled by said slide valve between each auxiliary chamber and the live steam space on the opposite side of said cylinder for retaining the valve in thrown position.

In testimony whereof I aflix my signature.

J OHAN NES KRllGER. 

